The invention described herein relates to a technological process and plant utilized therein, for deactivating the enzymes present in fruit and vegetables --tomatoes in particular.
Throughout the description, reference will in fact be made to the processing of tomatoes; nonetheless, the process and plant described herein may equally well be used for other produce--viz, fruit and vegetables in general.
When processing tomatoes--and especially when manufacturing tomato-pulp using the "Hot-Break" method--it is most important that the triturated, or minced tomato be heated to somewhere in excess of 90.degree. C. so as to as reduce enzyme-activity to a minimum, since, once a tomato is broken up, this tends to destroy pectins contained in the pulp, leading in consequence to a lack of density in the final product. In systems currently employed this is done either by a) heating the minced tomato by means of rotating coils in open-tank conditions, or b) mingling freshly-minced tomato with ready-heated mince, at normal atmospheric pressure. In either event the temperature of the tomato will never rise beyond 99.degree. C., since the plant functions at atmospheric pressure.
One advantage of the invention described herein is that it heats the minced tomato immediately to optimum temperature, from the point-of-view of enzyme-deactivation. Since the plant set forth herein is designed for pressurized operation, optimum temperature for deactivating enzymes might be determined--according to a given variety of produce--at anything between 95.degree. and 140.degree. C., since said temperature is no longer tied to conditions imposed by a plant functioning at atmospheric pressure.
A further advantage which the invention described herein offers over existing methods representative of the art, is that of enabling feed-in of the whole or minced tomato in a vacuum, thus preventing oxidization; indeed the mashing/chopping/mincing stage itself can be carried out under vacuum, with residual oxgen reduced to a minimum.